The vapour barrier on a Point Cook slab
Under the steel, under the whole slab, and branded.
In short: Three separate things can go wrong with a vapour barrier, and we have recorded all three here.
Position
It belongs beneath the steel. Laid over it, it neither blocks moisture properly nor protects the reinforcement.
Extent
It has to run under the entire slab. We have recorded it not extended beneath the whole footprint.
Branding
The standard requires a continuous printed marking identifying the product. Without it there is no way to confirm the membrane specified is the membrane installed.
Why all three matter
Each one on its own defeats part of the system, and none can be corrected after the pour.
When to look
The day before concrete, which is the only time any of it is visible.
Written by the Owner Inspections team from inspections carried out in Point Cook. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
